Luspatercept for the Treatment of Anemia Following Allogeneic Hematopoietic Stem Cell Transplantation(Allo-HSCT)

Inclusion Criteria:

1. Clinically diagnosed with acute leukemia.
2. Has undergone allogeneic hematopoietic stem cell transplantation (allo-HSCT).
3. Expected to survive for more than 3 months from the date of signing the informed consent form.
4. Willing and able to comply with scheduled visits, treatment plans, laboratory tests, and other study procedures, and has provided written informed consent.
5. Women of childbearing potential must have a negative serum pregnancy test within prior to enrollment. Female subjects who are surgically sterile or postmenopausal for at least 2 years are considered not of childbearing potential. Male and female subjects of reproductive potential must agree to use effective contraception throughout the study period.
6. Hemoglobin (Hb) level \< 80 g/L.

Exclusion Criteria:

1\. Inadequate organ function, defined as:

1. Creatinine clearance \< 60 mL/min;
2. Left ventricular ejection fraction (LVEF) \< 55%;
3. Oxygen saturation (SpO₂) \< 92% on room air;
4. Total bilirubin \> 2 × the upper limit of normal (ULN);
5. Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \> 3 × ULN. 2. Poorly controlled hypertension, defined as repeated systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg despite adequate antihypertensive therapy, or a history of hypertensive crisis or hypertensive encephalopathy.

3\. History of other malignancies (except for acute leukemia), unless the subject has been disease-free for ≥5 years. However, subjects with the following history/concomitant conditions are eligible:

1. Basal or squamous cell carcinoma of the skin;
2. Carcinoma in situ of the cervix;
3. Carcinoma in situ of the breast;
4. Incidental histological finding of prostate cancer (T1a or T1b as defined by the TNM staging system);
5. Solid tumors considered by the investigator to have no other known active disease.

4\. Major surgery within 8 weeks prior to enrollment. The subject must have fully recovered from any prior surgery.

5\. History of cerebrovascular accident (including ischemic, embolic, and hemorrhagic), transient ischemic attack, deep vein thrombosis (including proximal and distal), pulmonary or arterial embolism, arterial thrombosis, or other venous thrombosis within 6 months prior to enrollment. Note: Prior superficial thrombophlebitis is not an exclusion criterion.

6\. Uncontrolled epilepsy, history of cerebral ischemia/hemorrhage, cerebellar disease, or other active central nervous system disorders.

7\. Cardiac disease within 6 months prior to enrollment, including: myocardial infarction, uncontrolled angina, acute decompensated heart failure, New York Heart Association (NYHA) Class III-IV heart failure, or uncontrolled arrhythmia (as determined by the investigator).

8\. Uncontrolled active systemic fungal, bacterial, or viral infection. 9. Evidence of human immunodeficiency virus (HIV) infection, active hepatitis B, and/or active hepatitis C.

10\. History of pure red cell aplasia (PRCA) and/or anti-erythropoietin antibody.

11\. Any condition or concomitant medication that may interfere with the interpretation of study data.

12\. Known hypersensitivity to luspatercept or any of its excipients.